Piezoelectric cooling system

ABSTRACT

The present disclosure provides a piezoelectric system for controlling the temperature of a fluid. The system includes a body having a first portion and a second portion. The first portion is configured to be electrically coupled to a current source. The system also includes a membrane disposed between the first portion and second portion. The membrane is configured to be electrically coupled to the current source. A plurality of members is integrally coupled to the second portion and extend in a direction opposite the first portion. The plurality of members is configured to couple a fluid line to the system. The first portion or membrane is configured to receive a current from the current source to control a temperature output from the second portion.

FIELD OF THE INVENTION

The present invention relates to a closed-loop cooling system, and in particular a piezoelectric cooling system for cooling different fluids of a machine.

BACKGROUND OF THE INVENTION

Engine emission requirements have become more restrictive and require fewer pollutants from being emitted from powered machines. In order to meet these requirements, sub-systems and technologies are being added to base engine assemblies. Many of these sub-systems and technologies need to burn additional fuel to meet these requirements. By burning additional fuel, however, more heat is generated. As a result, larger and more complicated cooling systems are being incorporated into machines to meet increased cooling loads and requirements.

In a conventional machine, the temperature of fuel entering an engine is important for emissions output and system control. Cooling systems are conventionally arranged in a series of coolers. Fuel cooling systems are often mounted in front of or before the other machine cooling systems, such as a charge air, engine coolant, and hydraulic oil cooling system. In this arrangement, fresh air enters the machine and passes through a fuel cooling system and evaporator (or air conditioner condenser). With the machine producing additional heat to meet engine emission requirements, the air passing through the fuel cooling system and evaporator is warmed or preheated before passing through the other cooling systems. Thus, the other cooling systems have been made larger to further reduce the temperature of the air passing therethrough. The larger cooling systems, however, can be difficult to accommodate with the space limitations of many machines.

Therefore, it would be desirable to provide a more efficient and effective cooling system to overcome the additional heat produced by the machine without increasing the size of the system.

SUMMARY

In an exemplary embodiment of the present disclosure, a piezoelectric apparatus is provided for controlling the temperature of a fluid. The apparatus includes a body having a first portion and a second portion. The first portion is configured to be electrically coupled to a current source. A membrane is disposed between the first portion and second portion and is configured to be electrically coupled to the current source. The apparatus also includes a plurality of members coupled to the second portion and extends in a direction opposite the first portion. The plurality of members is configured to couple a fluid line to the apparatus. The first portion or membrane is configured to receive a current from the current source to control a temperature output from the second portion.

In one aspect of this embodiment, the second portion comprises an inlet and an outlet. In another aspect, the membrane comprises ceramic, quartz, or topaz. In a different aspect, the first portion is structured to receive electrical energy and increase in temperature and the plurality of members is structured to reduce in temperature. The membrane is structured to receive electrical energy and increase the temperature of the plurality of members. In addition, a temperature sensor is coupled to the second portion or plurality of members.

In another embodiment, a temperature control system is provided for a machine. The system includes a controller, an electrical energy source electrically coupled to the controller, and a piezoelectric device disposed in electrical communication with the controller. The piezoelectric device includes a body having a first portion and a second portion. The first portion is electrically coupled to the controller. The device also includes a membrane disposed between the first portion and second portion. The membrane is electrically coupled to the controller. Also, a plurality of members is coupled to the second portion and extends away from the first portion.

In one aspect, the electrical energy source and piezoelectric device are electrically coupled to one another. In another aspect, the system includes a first electrical flow path defined between the controller and membrane and a second electrical flow path defined between the controller and first portion. The temperature of the plurality of elements is controlled based on the direction of a signal passing through the first or second electrical flow path. For instance, the temperature decreases when current is passed through the second flow path to the first portion. Alternatively, the temperature increases when current is passed through the first flow path to the membrane.

In a related aspect, the system can include a fluid line coupled to the plurality of members. In addition, an inlet is disposed at one side of the second portion and an outlet is disposed at an opposite side thereof. The fluid line is configured to transport fluid from the inlet to the outlet. The system can include a temperature sensor disposed adjacent to the piezoelectric device where the temperature sensor is in electrical communication with the controller. The electrical energy source can be a battery or alternator. In a further aspect, the piezoelectric device is coupled to an engine or counterweight of the machine.

In a different embodiment, a method is provided for controlling a temperature of a fluid passing through a fluid line of a machine. The machine includes a controller, a current source electrically coupled to the controller, and a piezoelectric device electrically coupled to the controller. The piezoelectric device includes a plurality of members coupled to the fuel line. The method comprises receiving electrical energy from the current source, converting the received electrical energy into heat, dissipating the heat to induce a change in temperature of the plurality of members, and controlling the temperature of fluid passing through the fluid line.

In one aspect, the method includes measuring the temperature of fluid passing through the fluid line. In another aspect, the controlling step can include adjusting the amount of received current to increase or decrease the temperature of the plurality of members. In a different aspect, the method can include decreasing the fluid temperature when electrical energy is received by a first portion of the piezoelectric device and increasing the fluid temperature when electrical energy is received by a membrane portion of the piezoelectric device. In this aspect, the membrane portion is disposed between the first portion and the plurality of members.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of an excavator;

FIG. 2 is a side view of the excavator of FIG. 1 with a portion of an upper frame removed;

FIG. 3 is a partial top view of the excavator of FIG. 1 with a portion of an upper frame removed;

FIG. 4 is a partial perspective view of the excavator of FIG. 1 with a portion of an upper frame removed;

FIG. 5 is an exemplary schematic of a piezoelectric temperature control system;

FIG. 6 is a schematic of the temperature control system of FIG. 5 configured as a cooling system;

FIG. 7 is a schematic of the temperature control system of FIG. 5 configured as a heating system; and

FIG. 8 is a partial perspective view of an excavator including possible mounting locations of the piezoelectric cooling system.

Corresponding reference numerals are used to indicate corresponding parts throughout the several views.

DETAILED DESCRIPTION

The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.

An exemplary embodiment of a work machine is shown in FIG. 1. The machine is embodied as an excavator 100. The present disclosure is not limited, however, to an excavator and may extend to other work machines that have different cooling and heating needs. Referring to FIG. 1, the excavator 100 includes an upper frame 102 pivotally mounted to an undercarriage 104. The upper frame 102 can be pivotally mounted on the undercarriage 104 by means of a swing pivot 108. The upper frame 102 is rotatable about 360° relative to the undercarriage 104 on the swing pivot 108. A hydraulic motor (not shown) can drive a gear train (not shown) for pivoting the upper frame 102 about the swing pivot 108.

The undercarriage 104 can include a pair of ground-engaging tracks 106 on opposite sides of the undercarriage 104 for moving along the ground. Alternatively, the excavator 100 can include wheels for engaging the ground. The upper frame 102 includes a cab 110 in which the machine operator controls the machine. The cab 110 can include a control system (not shown) including, but not limited to, a steering wheel, a control level, control pedals, or control buttons. The operator can actuate one or more controls of the control system for purposes of operating the excavator 100.

The excavator 100 also includes a large boom 114 that extends from the upper frame 102 adjacent to the cab 110. The boom 114 is rotatable about a vertical arc by actuation of a pair of boom cylinders 116. A dipper stick or arm 118 is rotatably mounted at one end of the boom 114 and its position is controlled by a hydraulic cylinder 122. The opposite end of the boom 114 is coupled to the upper frame 102. At the end opposite the boom 114, the dipper stick or arm 118 is mounted to an excavator bucket 124 that is pivotable relative to the arm 118 by means of a hydraulic cylinder 120.

The upper frame 102 of the excavator 100 includes an outer shell cover to protect an engine assembly 112. At an end opposite the cab 110, the upper frame 102 includes a counterweight body 126. The counterweight 126 comprises a housing filled with material to add weight to the machine and offset a load collected in the bucket 124. The offset weight can improve the digging performance of the excavator 100.

Although FIG. 1 illustrates an excavator, the present disclosure is applicable to other machines besides an excavator. As such, the term “machine” will be used instead of excavator for purposes of this disclosure.

During operation, the machine generates significant heat and requires a cooling system to control the temperature of the engine 112 and other components of the machine. Referring to FIGS. 2-4, an exemplary cooling system 200 is shown. The cooling system 200 includes a radiator 202, a fuel cooler 204, and an air conditioner condenser 206. The cooling system 200 can also include a hydraulic oil cooler 208 and charge air cooler 210. The charge air cooler 210 can reduce the temperature of air passing through a turbocharger, for example. Air enters the charger cooler 210 through an inlet tube 316 and exits the turbocharger through a charger cooler tube 314. A fan shroud 312 is disposed adjacent to the radiator 202 and a fresh air intake 310 feeds air into the turbocharger. In FIG. 4, the fan shroud 312 is at least partially removed to better illustrate the cooling system 200 and other components of the machine. As shown, the engine 212 includes an engine head 308 and the machine can include an electronic control unit 300, a battery pack 212, and an alternator 302.

As shown in FIGS. 3-4, fresh air can enter the machine along a first direction indicated by arrow 304. In this embodiment, the cooling system 200 is configured on one side of the machine. In one example, the cooling system 200 and cab 110 can be configured on the same side of the machine. Fresh air is received by the cooling system 200, and in particular, is first received by the fuel cooler 204 and air conditioner condenser 206. Heat generated by the machine, including fluids passing through the fuel cooler 204, increase the temperature of the air. As previously described, the air is preheated as it passes by the fuel cooler 204 and air conditioner condenser 206. Thus, preheated air is then used to reduce the temperature of the hydraulic oil cooler 208 and charge air cooler 210. Since the preheated air is less effective at cooling the other coolers, engine emissions are unable to be limited or reduced. The preheated air exits the machine on an opposite side thereof as shown by arrow 306.

Referring to FIG. 5, an exemplary embodiment of a proposed temperature control system 500 is illustrated. The control system 500 is intended to take advantage of excess capacity of electrical energy stored in the machine's electrical system. This can be, for example, electrical energy stored in an alternator 302 or battery pack 212. In many conventional machine control systems, the alternator is not a custom-made component. An alternator, which converts mechanical energy into electrical current, can be provided in different increments of supplied current (e.g., in 20 amp increments). The alternator for a given machine is selected based on the electrical needs of the machine control system. For example, if the electrical control system requires 90 amps, an alternator that supplies 90 or more amps can be used. Therefore, if a 90-amp alternator is unavailable, a 100-amp alternator may be selected. In this instance, the alternator has an excess capacity of 10 amps not being used by the machine electrical control system.

The excess capacity of current can then be used by the control system 500 to control the temperature of different coolers of the machine (e.g., hydraulic oil cooler and charge air cooler). In addition, in the above example, the difference in size between an 80-amp alternator and a 100-amp alternator is usually insignificant. Thus, choosing an alternator which supplies additional current may not effect space limitations of the machine because the size of alternators can be about the same. This, of course, may not be true of an alternator that supplies 300 amps compared to an alternator that supplies 100 amps. As a result, the selected alternator may depend on space limitations of the machine. The same is true if the control system 500 is using excess electrical energy from the machine battery 212.

The control system 500 also includes an electronic control unit 300. The electronic control unit 300, or ECU, can be electrically coupled to a machine controller (not shown). Alternatively, the ECU 300 can be the same as the machine controller. The ECU 300 can also be electrically coupled to the alternator 302 via electrical connection 532 and the battery 212 via electrical connection 528. The battery 212 and alternator 302 are electrically coupled to one another via electrical connection 530. As a result, a signal such as current can pass between the ECU 300, battery 212, alternator 302 and machine controller (if not part of the ECU). Each of the ECU 300, battery 212, and alternator 302 are coupled to ground as shown by arrows 520.

The control system 500 also includes a piezoelectric system 504. The piezoelectric system 504 can include a first portion 506 and a second portion 510. A membrane 508 formed of piezoelectric material (e.g., ceramic, quartz, topaz, etc.) is disposed between the first portion 506 and second portion 510. The second portion 510 of the piezoelectric system 504 can also include a plurality of arms or members 512 extending therefrom. A hose, pipe, tube, or other elongated member carrying a fluid such as gas, diesel fuel, air, oil, etc. can be coupled to the plurality of arms or members 512. In FIG. 5, for example, a fluid line 514 is coupled to the piezoelectric system 504 via the plurality of arms or members 512. The plurality of arms or members 512 can be in the form of hooks, clamps, clasps, clips, or other attachment means. A fluid line 514 is coupled to the piezoelectric system 504 at both an inlet 516 and an outlet 518. Fluid therefore can pass through the piezoelectric system 504 by entering at the inlet 516 having a first temperature and exiting at the outlet 518 having a second temperature. If the piezoelectric system 504 is structured as a cooling system, the first temperature will be greater than the second temperature. If, however, the piezoelectric system 504 is structured as a heating system, the first temperature will be less than the second temperature.

The piezoelectric system 504 is electrically coupled to the ECU 300 by means of a first electrical connection 524 and a second electrical connection 526. The ECU 300 can receive current from the alternator 302 or battery 212 and send a portion or all of the current to the piezoelectric system 504 to either heat or cool the fluid passing through the fluid line 514. A temperature sensor 502 can be disposed near the outlet 518 of the piezoelectric system 504 to measure the temperature of fluid exiting the system. Alternatively, the temperature sensor 502 can be coupled to the outlet 518 of the system 504.

Referring to FIG. 6, the piezoelectric system 504 is configured as a cooling system. As shown, the temperature sensor 502 is coupled to the outlet 518 of the piezoelectric system 504 via an electrical connection 522. Thus, as the sensor 502 measures the temperature of the fluid, the sensor 502 can communicate with the ECU 300 by a sending a signal via electrical connection 522. The ECU 300 can receive and interpret the signal and send more or less current to the piezoelectric system 504.

To cool the temperature of the fluid at the outlet 518, the ECU 300 can send a current received from the alternator 302 or battery 212 to the first portion 506 of the system 504 via electrical connection 602. A return connection 600 is disposed between the membrane 508 and ECU 300. The piezoelectric system 504 receives the current and converts the electrical energy into heat at the first portion 506 of the system 504. As the first portion 506 is heated, the second portion 510 of the system is cooled. As the second portion 510 cools, the plurality of arms 512 dissipate heat and provide a cooling effect to the fluid line 514. This in turn can reduce the temperature of the fluid passing through the fluid line 514.

As the piezoelectric system 504 cools the temperature of the fluid passing through the fluid line 514, the temperature sensor 502 can continuously communicate this temperature to the ECU 300. If the temperature detected by the sensor 502 is greater than the desired temperature, the ECU 300 can send additional current to the piezoelectric system 504 to generate more cooling. For instance, to increase the cooling effect more rapidly, the ECU 300 may transfer the maximum amount of current the piezoelectric system can handle. If the detected temperature reaches the desired temperature, the ECU 300 can reduce the amount of current transferred to the piezoelectric system 504. The desired temperature can be a threshold parameter. Alternatively, the desired temperature can be set or adjusted by the machine controller.

With reference to FIG. 7, the piezoelectric system 504 can also increase the temperature of the fluid passing through the fluid line 514. Diesel engines, for example, can struggle to start at extremely cold temperatures (e.g., −30° C.). In this and related applications, it can be desirable to preheat the fluid such as diesel fuel or gasoline entering the engine to facilitate better starting performance. To do so, the piezoelectric system 504 can be positioned on the machine so that fluid entering the engine first passes through the system 504. Referring to FIG. 7, the ECU 300 can send current to the piezoelectric system 504 in a reverse manner compared to that shown in FIG. 6. Current is transferred to the piezoelectric system 504 along a first connection 700 such that the first portion 506 of the system is cooled and the second portion 510 is heated. As the second portion 510 is heated, the fluid line 514 and fluid passing therethrough is also heated. A second electrical connection 702 is also provided between the ECU 300 and piezoelectric system 504.

The temperature sensor 502 communicates the rising temperature of the fluid with the ECU 300. The ECU 300 can adjust the amount of current sent to the piezoelectric system 504 based on the temperature of the fluid. If the measured fluid temperature is less than a desired temperature, the ECU 300 can send more current to the system 504 to generate an increase in temperature. If the measured fluid temperature reaches the desired temperature, the ECU 300 can reduce the amount of or stop transferring current to the piezoelectric system 504.

In FIG. 8, an embodiment of a machine such as an excavator having a counterweight 126 is shown. The arrangement of a cooling system 200, alternator 302, fan shroud 312, and fluid lines is similar to that shown in FIGS. 2-4. The present disclosure extends beyond the scope of what is illustrated in FIGS. 2-4 and 8, but these figures do illustrate an exemplary embodiment of the present disclosure. FIG. 8, in particular, illustrates a plurality of locations to which the piezoelectric control system 504 can be coupled. For example, a first location 800 and a second location 802 are provided on a panel or wall 808 of the counterweight 126. In either location, the piezoelectric control system 504 can operably control the temperature of fluid entering the engine or turbocharger.

An alternative location is at or on the engine head 308. For instance, a third location 804 and fourth location 806 are provided on the engine head 308, which is disposed above the valve cover. At one of these two locations, fluid entering the engine can be cooled by the piezoelectric control system 504 and therefore better engine emissions can be achieved.

Depending on the machine, there may be additional locations to which a piezoelectric control system 504 is mounted. By positioning the control system 504 at a location near an inlet of a working component, such as an engine or turbocharger, fluid temperature can be controlled more easily to achieve better vehicle performance and reduced emissions.

In addition, the piezoelectric control system 504 can operate from electrical energy supplied by any electrical storage device. While an alternator and battery have been described with reference to the illustrated embodiments, any electrical storage device capable of supplying current to the piezoelectric control system 504 is contemplated by the present disclosure. This may even include electrical energy supplied by an electric outlet or electrical-generating mechanism.

While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 

1. A piezoelectric apparatus for controlling the temperature of a fluid, comprising: a body having a first portion and a second portion, the first portion configured to be electrically coupled to a current source; a membrane disposed between the first portion and second portion, the membrane configured to be electrically coupled to the current source; and a plurality of members coupled to the second portion and extending in a direction opposite the first portion, the plurality of members configured to couple a fluid line to the apparatus; wherein, the first portion or membrane is configured to receive a current from the current source to control a temperature output from the second portion.
 2. The apparatus of claim 1, wherein the second portion comprises an inlet and an outlet.
 3. The apparatus of claim 1, wherein the membrane comprises ceramic, quartz, or topaz.
 4. The apparatus of claim 1, wherein: the first portion is structured to receive electrical energy and increase in temperature; and the plurality of members is structured to reduce in temperature.
 5. The apparatus of claim 1, wherein the membrane is structured to receive electrical energy and increase the temperature of the plurality of members.
 6. The apparatus of claim 1, further comprising a temperature sensor coupled to the second portion or plurality of members.
 7. A temperature control system for a powered machine, comprising: a controller; an electrical energy source electrically coupled to the controller; and a piezoelectric device disposed in electrical communication with the controller, the piezoelectric device comprising: a body having a first portion and a second portion, the first portion being electrically coupled to the controller; a membrane disposed between the first portion and second portion, the membrane being electrically coupled to the controller; and a plurality of members coupled to the second portion and extending away from the first portion.
 8. The system of claim 7, wherein the electrical energy source and piezoelectric device are electrically coupled to one another.
 9. The system of claim 7, further comprising: a first electrical flow path defined between the controller and membrane; and a second electrical flow path defined between the controller and first portion; wherein, the temperature of the plurality of elements is controlled based on the direction of a signal passing through the first or second electrical flow path.
 10. The system of claim 9, wherein the temperature decreases when the signal is passed through the second flow path to the first portion.
 11. The system of claim 9, wherein the temperature increases when the signal is passed through the first flow path to the membrane.
 12. The system of claim 7, further comprising a fluid line coupled to the plurality of members.
 13. The system of claim 12, further comprising an inlet disposed at one side of the second portion and an outlet disposed at an opposite side thereof, wherein the fluid line is configured to transport fluid from the inlet to the outlet.
 14. The system of claim 7, further comprising a temperature sensor disposed adjacent to the piezoelectric device, the temperature sensor being in electrical communication with the controller.
 15. The system of claim 7, wherein the electrical energy source comprises a battery or alternator.
 16. The system of claim 7, wherein the piezoelectric device is coupled to an engine or counterweight of the machine.
 17. A method of controlling a temperature of a fluid passing through a fluid line of a machine, the machine including a controller, a current source electrically coupled to the controller, and a piezoelectric device electrically coupled to the controller and including a plurality of members coupled to the fuel line, the method comprising: receiving electrical energy from the current source; converting the received electrical energy into heat; dissipating the heat to induce a change in temperature of the plurality of members; and controlling the temperature of fluid passing through the fluid line.
 18. The method of claim 17, further comprising measuring the temperature of fluid passing through the fluid line.
 19. The method of claim 17, wherein the controlling step comprises adjusting the amount of received electrical energy to increase or decrease the temperature of the plurality of members.
 20. The method of claim 17, further comprising: decreasing the fluid temperature when electrical energy is received by a first portion of the piezoelectric device; and increasing the fluid temperature when electrical energy is received by a membrane portion of the piezoelectric device, where the membrane portion is disposed between the first portion and the plurality of members. 